package com.aat.dxfy.jiajiemi.pfx;
import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.security.Key;
 import java.security.SecureRandom;
 
 import javax.crypto.Cipher;
 import javax.crypto.CipherInputStream;
 import javax.crypto.CipherOutputStream;
 import javax.crypto.KeyGenerator;
 import javax.crypto.SecretKey;
 import javax.crypto.SecretKeyFactory;
 import javax.crypto.spec.DESKeySpec;
 
 /**
  * <p>
  * DES加密解密工具包
  * </p>
  * 
  * @author IceWee
  * @date 2012-5-19
  * @version 1.0
  */
 public class DESUtils {
     
     private static final String ALGORITHM = "DES";
     private static final int CACHE_SIZE = 1024;
 
     /**
      * <p>
      * 生成随机密钥
      * </p>
      * 
      * @return
      * @throws Exception
      */
     public static String getSecretKey() throws Exception {
         return getSecretKey(null);
     }
     
     /**
      * <p>
      * 生成密钥
      * </p>
      * 
      * @param seed 密钥种子
      * @return
      * @throws Exception
      */
     public static String getSecretKey(String seed) throws Exception {
         SecureRandom secureRandom;
         if (seed != null && !"".equals(seed))
             secureRandom = new SecureRandom(seed.getBytes());
         else
             secureRandom = new SecureRandom();
         KeyGenerator keyGenerator = KeyGenerator.getInstance(ALGORITHM);
         keyGenerator.init(secureRandom);
         SecretKey secretKey = keyGenerator.generateKey();
         return Base64Utils.encode(secretKey.getEncoded());
     }
     
     /**
      * <p>
      * 加密
      * </p>
      * 
      * @param data
      * @param key
      * @return
      * @throws Exception
      */
     public static byte[] encrypt(byte[] data, String key) throws Exception {
         Key k = toKey(Base64Utils.decode(key));
         Cipher cipher = Cipher.getInstance(ALGORITHM);
         cipher.init(Cipher.ENCRYPT_MODE, k);
         return cipher.doFinal(data);
     }
     
     /**
      * <p>
      * 文件加密
      * </p>
      * 
      * @param key
      * @param sourceFilePath
      * @param destFilePath
      * @throws Exception
      */
     public static void encryptFile(String key, String sourceFilePath, String destFilePath) throws Exception {
         File sourceFile = new File(sourceFilePath);
         File destFile = new File(destFilePath); 
         if (sourceFile.exists() && sourceFile.isFile()) {
             if (!destFile.getParentFile().exists()) {
                 destFile.getParentFile().mkdirs();
             }
             destFile.createNewFile();
             InputStream in = new FileInputStream(sourceFile);
             OutputStream out = new FileOutputStream(destFile);
             Key k = toKey(Base64Utils.decode(key));
             Cipher cipher = Cipher.getInstance(ALGORITHM);
             cipher.init(Cipher.ENCRYPT_MODE, k);
             CipherInputStream cin = new CipherInputStream(in, cipher);
             byte[] cache = new byte[CACHE_SIZE];
             int nRead = 0;
             while ((nRead = cin.read(cache)) != -1) {
                 out.write(cache, 0, nRead);
                 out.flush();
             }
             out.close();
             cin.close();
             in.close();
         }
     }
     
     /**
      * <p>
      * 解密
      * </p>
      * 
      * @param data
      * @param key
      * @return
      * @throws Exception
      */
     public static byte[] decrypt(byte[] data, String key) throws Exception {
         Key k = toKey(Base64Utils.decode(key));
         Cipher cipher = Cipher.getInstance(ALGORITHM);
         cipher.init(Cipher.DECRYPT_MODE, k);
         return cipher.doFinal(data);
     }
     
     /**
      * <p>
      * 文件解密
      * </p>
      * 
      * @param key
      * @param sourceFilePath
      * @param destFilePath
      * @throws Exception
      */
     public static void decryptFile(String key, String sourceFilePath, String destFilePath) throws Exception {
         File sourceFile = new File(sourceFilePath);
         File destFile = new File(destFilePath); 
         if (sourceFile.exists() && sourceFile.isFile()) {
             if (!destFile.getParentFile().exists()) {
                 destFile.getParentFile().mkdirs();
             }
             destFile.createNewFile();
             InputStream in = new FileInputStream(sourceFile);
             OutputStream out = new FileOutputStream(destFile);
             Key k = toKey(Base64Utils.decode(key));
             Cipher cipher = Cipher.getInstance(ALGORITHM);
             cipher.init(Cipher.DECRYPT_MODE, k);
             CipherOutputStream cout = new CipherOutputStream(out, cipher);
             byte[] cache = new byte[CACHE_SIZE];
             int nRead = 0;
             while ((nRead = in.read(cache)) != -1) {
                 cout.write(cache, 0, nRead);
                 cout.flush();
             }
             cout.close();
             out.close();
             in.close();
         }
     }
 
     /**
      * <p>
      * 转换密钥
      * </p>
      * 
      * @param key
      * @return
      * @throws Exception
      */
     private static Key toKey(byte[] key) throws Exception {
         DESKeySpec dks = new DESKeySpec(key);
         SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(ALGORITHM);
         SecretKey secretKey = keyFactory.generateSecret(dks);
         return secretKey;
     }
     
 }